/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: DupFilterIterator.java,v 1.2.4.1 2005/09/06 06:16:11 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.dom;

import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary;
import com.sun.org.apache.xalan.internal.xsltc.util.IntegerArray;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.dtm.ref.DTMAxisIteratorBase;
import com.sun.org.apache.xml.internal.dtm.ref.DTMDefaultBase;

/**
 * Removes duplicates and sorts a source iterator. The nodes from the
 * source are collected in an array upon calling setStartNode(). This
 * array is later sorted and duplicates are ignored in next().
 *
 * @author G. Todd Miller
 */
public final class DupFilterIterator extends DTMAxisIteratorBase {

  /**
   * Reference to source iterator.
   */
  private DTMAxisIterator _source;

  /**
   * Array to cache all nodes from source.
   */
  private IntegerArray _nodes = new IntegerArray();

  /**
   * Index in _nodes array to current node.
   */
  private int _current = 0;

  /**
   * Cardinality of _nodes array.
   */
  private int _nodesSize = 0;

  /**
   * Last value returned by next().
   */
  private int _lastNext = END;

  /**
   * Temporary variable to store _lastNext.
   */
  private int _markedLastNext = END;

  public DupFilterIterator(DTMAxisIterator source) {
    _source = source;
// System.out.println("DFI source = " + source + " this = " + this);

    // Cache contents of id() or key() index right away. Necessary for
    // union expressions containing multiple calls to the same index, and
    // correct as well since start-node is irrelevant for id()/key() exrp.
    if (source instanceof KeyIndex) {
      setStartNode(DTMDefaultBase.ROOTNODE);
    }
  }

  /**
   * Set the start node for this iterator
   *
   * @param node The start node
   * @return A reference to this node iterator
   */
  public DTMAxisIterator setStartNode(int node) {
    if (_isRestartable) {
      // KeyIndex iterators are always relative to the root node, so there
      // is never any point in re-reading the iterator (and we SHOULD NOT).
      boolean sourceIsKeyIndex = _source instanceof KeyIndex;

      if (sourceIsKeyIndex
          && _startNode == DTMDefaultBase.ROOTNODE) {
        return this;
      }

      if (node != _startNode) {
        _source.setStartNode(_startNode = node);

        _nodes.clear();
        while ((node = _source.next()) != END) {
          _nodes.add(node);
        }

        // Nodes produced by KeyIndex are known to be in document order.
        // Take advantage of it.
        if (!sourceIsKeyIndex) {
          _nodes.sort();
        }
        _nodesSize = _nodes.cardinality();
        _current = 0;
        _lastNext = END;
        resetPosition();
      }
    }
    return this;
  }

  public int next() {
    while (_current < _nodesSize) {
      final int next = _nodes.at(_current++);
      if (next != _lastNext) {
        return returnNode(_lastNext = next);
      }
    }
    return END;
  }

  public DTMAxisIterator cloneIterator() {
    try {
      final DupFilterIterator clone =
          (DupFilterIterator) super.clone();
      clone._nodes = (IntegerArray) _nodes.clone();
      clone._source = _source.cloneIterator();
      clone._isRestartable = false;
      return clone.reset();
    } catch (CloneNotSupportedException e) {
      BasisLibrary.runTimeError(BasisLibrary.ITERATOR_CLONE_ERR,
          e.toString());
      return null;
    }
  }

  public void setRestartable(boolean isRestartable) {
    _isRestartable = isRestartable;
    _source.setRestartable(isRestartable);
  }

  public void setMark() {
    _markedNode = _current;
    _markedLastNext = _lastNext;    // Bugzilla 25924
  }

  public void gotoMark() {
    _current = _markedNode;
    _lastNext = _markedLastNext;    // Bugzilla 25924
  }

  public DTMAxisIterator reset() {
    _current = 0;
    _lastNext = END;
    return resetPosition();
  }
}
